|09-08-10, 04:04 PM||#1|
Join Date: Jul 2010
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Hawts and Vawts
One or two points from one not greatly endowed with wind power knowledge. Bob McGovern's two posts on small wind power seemed full of good sense to me. I have n't been very impressed with much else I've read (Hugh Piggott also seems pretty good) in an subject area which seems to be fashionable and therefore full of charlatans out to make a quick buck .As B Mcg says of the many small wind power systems "..what a poor lot they are.." .I would extend this description to 90% of whats written on small wind systems.
To get to my points, I have a sneaky preference for Vawts somewhat modified by B McG's comments which seemed pretty sensible to me. However Vawts definitely win on aesthetics. Bob mentions the downwind blades are in the wind shadow of the upwind blade. Presumably this point would not be true for the most aesthetic version with helical blades ?
Secondly due to 1/the possibility of at least two bearings to the Vawt rotor , with a third easily added centrally.
2/ Some balance of rotor stresses by using helical blades and extending these above and below the top and bottom bearings.
3/ Potentially stronger blades supported at at least two points for a vawt.
4/ A much lower TSR
..I feel instinctively a Vawt should be able to stand much higher operating wind speeds than a Hawt and therefore be able to extract larger amounts of power from high wind speeds at exactly the time a Hawt has to furl to avoid damage. Less maintenance should be an additional bonus.
Surely these points must be significant in narrowing the gap between Hawts and Vawts. Any comments anyone. Big Al.
|bob mcgovern, wind|